Lots of steam in exhaust

[Leon_vanos]

My seacock is very questionable but I did blow into it and it didn’t seem to have any blockage. I was hoping not to have to replace it until I haul out in the future. It is one of the old pvc seacocks. I ran a hose from the splitter in between the seacock and water pump into a bucket of freshwater but it didn’t seem to make a difference. The hose is 3 foot long and I put the 5 gal water bucket right to the side of the engine compartment but it didn’t suck water very well at all. Could the hose be to Long? Would it be a bad idea to connect the dock water hose directly into the splitter to see if the increased water flow improves the overheating and steam because it’s too much water pressure? If it does improve then I can confirm it is the seacock causing all the problems.

[Leon_vanos]

It is probably the original seacock from 1978 which is pretty scary.

[Leon_vanos]

Thanks Hanley! Ill try both of those test and get back.

[hanleyclifford]

It is probably the original seacock from 1978 which is pretty scary.

You could disconnect the hose, open the valve and see what kind of flow you see.

[hanleyclifford]

My seacock is very questionable but I did blow into it and it didn’t seem to have any blockage. I was hoping not to have to replace it until I haul out in the future. It is one of the old pvc seacocks. I ran a hose from the splitter in between the seacock and water pump into a bucket of freshwater but it didn’t seem to make a difference. The hose is 3 foot long and I put the 5 gal water bucket right to the side of the engine compartment but it didn’t suck water very well at all. Could the hose be to Long? Would it be a bad idea to connect the dock water hose directly into the splitter to see if the increased water flow improves the overheating and steam because it’s too much water pressure? If it does improve then I can confirm it is the seacock causing all the problems.

It is important that the hose from the seacock to the pump NOT rise above the water line and then descend to the pump.

[hanleyclifford]

It is probably the original seacock from 1978 which is pretty scary.

My boat came with a 1/2" thru hull. I replaced it with a 3/4" and ran that for a few years. Then I switched to a 1" - just to be certain.

[Leon_vanos]

When I disconnect the hose and open the valve I get no water flowing through. I should see water gushing out?

[Dave Neptune]

Yes water should gush out depending on how far below the waterline.

Did you rebuild your water pump or replace the impeller? If so did you check the width of the impeller? If it does not fit snug on the sides it will really reduce to pressure and volume of the pump.

I did look at your video again and that is very little water flowing from the exhaust.

Are you using a t-stat? If not did you close the bypass valve some or pinch the bypass line forcing more water through the block to increase cooling?

I would suspect the bottom valve in your set up to be the culprit as there is no reason to ad another unless something was wrong with the first one. Be worth cleaning that set up up. You may try forcing some water through the thru hull with a hose, could be just something stuck in there or even growth.

Dave Neptune

[Leon_vanos]

Dave, The water pump is brand new straight from Moyer marine so it’s in good shape and the right size impeller. I removed the t stat to test it and see if improved my water flow running without it installed. Water flow stayed the same. T stat works but currently still out but I will re install it. I tried running with the bypass closed and still get steam and overheating. I actually have very good water flow at idle and low rpm’s. Thanks for the idea of running water through the through hull, I will try that. Gonna see if running freshwater through the t valve after the seacock will improve conditions. Could a small restriction in the seacock potential cause so much steam? Even with having good water flow under 150 degrees? Also is it difficult replacing a seacock in water? Would a video of the water flow at idle help to see?
Thanks for all the help everyone!

[Dave Neptune]

Replacing in the water is not a big deal but you MUST be absolutely prepared and ready. I have done it a few times. Do have a tapered plug handy just incase. I have even swapped out a prop shaft in the water. Never really had a problem and only once did I get enough water in before installing to set off my bilge pump.

Be sure that you are turning the valve and not the thru hull, that can create another can of worms.

Take a good look and have everything laid out that you may need.

Dave Neptune

[ndutton]

Hold on a minute. Before you go attacking the thru-hull valve please do this simple test first:

1. Close the valve
2. Remove the hose attached to the valve
3. Open the valve briefly to observe flow - or not. If generous flow is observed, that's not your problem, time to look downstream. If no flow or poor flow →
4. Close the valve
5. Remove all fittings threaded into the valve.
6. Get a small rod, stick or other probe of suitable diameter (smaller than the valve opening) and length
7. Open the valve
8. Insert the probe and clear the thru-hull of obstruction, growth, etc. "Rod it out", sort of a roto-rooter treatment
9. Close the valve, reassemble and retest.

I've had two instances of growth blocking a thru-hull and one instance of a small fish swimming up in there clogging up the works. Pulled off the hose and there was a fish head looking back at me.

[Leon_vanos]

Update on the engine.
I replaced the seacock and have very good water flow now coming out while the seacock is open (so no blockage in the seacock or through hull) my engine is running a lot cooler at 150-160 under load but I still have the same amount of steam. So I’ve done a compression test and am getting 90 in every cylinder, pressure test is holding 15 psi for an hour in the block and manifold, replaced the exhaust elbow with Moyer marine exhaust and changed the exhaust hoses. Also replaced the vetus water lock. Water pump is brand new from Moyer marine. No oil or water leaks anywhere and the oil is clean. Plugs have a little bit of fouling in cylinder 4 and 3. Great water flow at idle and steam starts when engine temp gets to around 140 and gets worse when temp gets higher and seems to be less water flow with steam. I haven’t got the exhaust back pressure test but with all new exhaust, hoses, vetus water lift, and no obstructions I would think it is good. Is it possible that water is getting into the cylinders? I’m not sure what to test next. Also still getting power loss under close to full rpm. Any advice would be greatly appreciated! Thanks

[hanleyclifford]

My seacock is very questionable but I did blow into it and it didn’t seem to have any blockage. I was hoping not to have to replace it until I haul out in the future. It is one of the old pvc seacocks. I ran a hose from the splitter in between the seacock and water pump into a bucket of freshwater but it didn’t seem to make a difference. The hose is 3 foot long and I put the 5 gal water bucket right to the side of the engine compartment but it didn’t suck water very well at all. Could the hose be to Long? Would it be a bad idea to connect the dock water hose directly into the splitter to see if the increased water flow improves the overheating and steam because it’s too much water pressure? If it does improve then I can confirm it is the seacock causing all the problems.

I don't like that "splitter" hose in the T bringing water to the pump. If it leaks even a little air it can disrupt water flow. If you do connect directly to dockside water you must be very careful to avoid getting water into the engine. I do it all the time on my boat but you must be right there to close or limit the flow from the dockside hose. Even a few seconds can be disastrous if you're not paying attention. Exactly why the procedure is not well thouight of on this forum. But at this point for you it might be worth the risk. Plan the exercise carefully. Start the engine dry and as soon as it is running start feeding the water in a little at a time. Watch the transom exit. Helps to have an assistant.

[Easy Rider]

Seems to me the problem could be that your not getting enough water through to the engine when the rev's are up and under load. I would begin by simplifying the set up you have between the through hull and the pump. One length of hose with minimum bends and no other connections. This would lessen the possibility of air entering the line with your present setup. Another thought is that if you have a strainer over the intake on the exterior of the hull you could still have some crud on it and as you increase the power it could be sucking some of that crud over the screen increasing the restriction to the flow. I would get this cleared up before looking at the engine for a solution.